270 THE STATUS OF MAN. 



cies, they are a menace to a real unity of the nation, to the de- 

 mocracy which is so popular nowadays. 



If we leave the question of immigration for the present, we 

 are confronted with the following question: Are we, within 

 the boundaries of a nation always concerned with one species 

 in the biological sense or is it possible that more than one spe- 

 cies of men coexist in one nation? 



From a political standpoint an answer to this question is 

 of the very greatest importance, as we will presently see. 

 This question is not to be decided by opinion, it is a matter 

 of research. It would be possible so to arrange an enquiry, as 

 to find out, in how far there exists within a nation classes of 

 people which are separate species, classes within which mar- 

 riages are so much commoner than marriages between members 

 of different classes, that they assume the rank of species. And 

 it should not be superlatively difficult to find out, what cause 

 or combinations of causes are most effective to bring about 

 this great preponderance of intra-specific marriages. In this 

 connection we must remember the slow rate of reproduction 

 and the small infant mortality in man, which makes it prob- 

 able that only barriers of a certain magnitude, or combina- 

 tions of barriers which assist each other's action, can bring 

 about or continue a specific diversity in man. 



How do specific differences within one nation originate? If 

 we do not consider cases in which two different peoples live 

 together within the political boundary of a country, cases 

 in which such peoples tend to segregate, especially if they use 

 a different language, the best examples of species within a na- 

 tion are furnished by castes. Are castes within a nation of 

 such a nature that their differentiation can be inferred? In sev- 

 eral instances it is clear, that the specific difference between 

 castes in a nation is not brought about by any cause or set of 

 causes differentiating what once was one species, but by im- 

 migration. Immigrants of one species coming into a country 

 in numbers big enough and with a strong enough tendency to 

 marry with their kind will not merge into the older inhabi- 



